A. Field of the Invention
The invention relates to systems for the presence recognition of a second portable data carrier by a first portable data carrier.
B. Related Art
When using an electronic health card, in certain application cases it is necessary to determine the presence of a doctor before data of the electronic health card can be accessed. To determine and check the presence of a doctor, between a patient's electronic health card (a portable data carrier) and the doctor's so-called health professional card (also in the form of a portable data carrier) an authentication must be carried out. This authentication is initiated by a terminal, with which the electronic health card and the health professional card are in communicative connection, as a host. Subsequently, the authentication is effected via a security module (SMC-A) of the terminal, upon which the communication taking place within the framework of the authentication between electronic health card and health professional card must be tunnelled in the terminal. After effected authentication, the health professional card, however, can be removed unnoticedly, the authentication remaining valid and thus the electronic health card can be further accessed.
There is thus a need for presence recognition between two data carriers.
If several contactless data carriers, such as e.g. chip cards, are located in the response range of an RFID reading device, in particular according to ISO/IEC 14443 type A or type B, the reading device (i.e. the terminal) can set up with each of the contactless data carriers in the field of its antenna (so-called response range) a communication relation. A direct communication from data carrier to data carrier, however, is not possible, as the data carriers typically do not have means for detecting the load modulation of another data carrier. The possible realization of such a load modulation detector on a portable data carrier is additionally impeded by the usually employed modulation methods (ISO/IEC 14443: Load modulation with an auxiliary carrier at a frequency of 848 kHz). A communication from data carrier to data carrier is thus, according to the prior art, only unfavorably possible with involvement of the reading device.
From DE 10 2007 022 943 A1 as the closest prior art there is known a system consisting of a reading device and several data carriers. The reading device supplies all data carriers with energy via a contactless field. In order to make it possible for a data carrier to carry out a conflict-free direct communication with a second data carrier, the reading device is put into a wait mode by the first data carrier and the first data carrier into an active communication mode.
From DE 10 2004 058 165 there is known a contactless data carrier which has, in addition to a contactless data interface, for example on the basis of infrared or radio transmission, a receiving device for receiving energy which is contactlessly transmitted separate from the data. This embodiment aims to achieve that also a portable data carrier which has no or no sufficient own energy source can carry out a contactless data transmission for which a comparatively high amount of energy is required. In particular, to the portable data carrier there are to be opened up transmission techniques for the contactless data transmission, which otherwise are less well suited for a contactless energy transfer.
It is the object of the present invention to state systems which make possible a simple presence recognition between two portable data carriers.